I have a '61 C60 with the 261 6 cyl.;I will dig some out but I couldn't find a pic right now. I lucked out that mine's all original bought from the farmer that had it since '64. He bought it from a local lumberyard that had several; they bought them all new and then traded the whole fleet in for new '64's with V8's. So it's almost kinda sorta a one owner. That front suspension you mentioned they only ran for two years, but parts are still available if you look. This site is worth a million $$ in the insight & info you will get! That V6 will pull anything you load up. My dad had told me that the GMC's prior to maybe '58(?) were positive ground but that they had standardized afterward. Might have more likely been when they went to 12v, which should have been '55. Interestingly, when I got my Chevy it was actually running positive ground! I called the excellent auto electric shop we have here and asked him what's the deal. He said someone had gotten it crossed up at some point and switched the polarity. Besides changing how your ignition parts wear and the danger of crossing jumper cables etc. it wasn't really hurting anything. I had called him about rebuilding the generator & regulator; he said pull them, bring them in and when you get them back switch your cables back to negative ground. I did that, all is back as it should be and running fine.